Hydraulic brake cylinder and method of making same



April 18, 1939. J. w. L ElGHToN 2,154,317

HYDRAULIC BRAKE CYLINDER AND METHOD OF MAKING SAME Filed Feb. 13, 1956 2Sheets-Sheet l m vm wd( N a um April 18, 1939- J. w. LElGHToN 2,154,817

HYDRAULIC BRAKE CYLINDER AND METHOD OF`MAKING SAME Filed Feb. 13, 1936 2Sheets-Sheet 2 M, YM

ATTORN EY.

Patented Appr. 1s, 1939 UNITED STATES PATENT oFFlcE HYDRAULIC BRAKECYLINDER AND METH- OD F MAKING SA'ME 7 Claims.

This invention relates to hydraulic brake cylinder assemblies. Moreparticularly it relates to a novel form of hydraulic brake cylinder andmounting therefor including a construction which provides novel, simpleand effective means for introducing the fluid to the interior of thebrake cylinder and bleeding the same.

'Ihe primary object of the present invention is to provide a hydraulicbrake cylinder construction which is extremely simple and rugged, andwhich is exceptionally cheap to manufacture.

Another object of the present invention consists in the provision of ahydraulic brake cylinder construction which is composed substantiallyentirely of sheet metal parts and which is very easily and convenientlyassembled.

A still. further object of the present invention consists in theprovision of a method of manufacturing hydraulic brake cylinderassemblies which contemplates an exceedingly cheap, eil'ective andsimple process of producing the novel brake cylinder construction of thepresent invention.

Many other and further objects and advantages of the present inventionwill become clearly apparent from the following specication whenccnsidered in connection with the accompanying drawings forming a partthereof.

In the drawings:

Figure l is a plan view, with portions broken away, of one embodiment ofthe improved brake cylinder construction of the present invention,illustrating the same mounted on a conventional brake housing insubstantially the position the apparatus is designed to occupy duringactual use;

Fig. 2 is a sectional View, taken substantially on the line 2-2 of Fig.1, illustrating in detail the parts for supporting the brake cylinderconstruction and showing the ports which provide communication to theinterior thereof;

Fig. 3 is a transverse, sectional view, taken substantially on the line3 3 of Fig. 1, showing in detail the connection of the mounting means tothe brake cylinder and the ports which provide'communication to theinterior thereof;

Fig. 4 is a plan view of a modified form of the invention, showing aconstruction in which the supporting means for the brake cylinder is ofa dift'erent and novel construction;

Fig. 5 is a sectional view, taken substantially on the line 5-5 of Fig.4, illustrating in detail the construction ot the modled form ofmounting means;

Fig. 6 is a sectional view, taken substantially on the line 6 6 of Fig.4, illustrating in detail the construction and arrangement of the portwhich communicates with the interior of the modified cylinderconstruction;

Fig. '7 is a transverse, sectional view through a Il still furthermodified form of the invention, showing a construction in which integralportions of the cylinders provide a structure for forming the portscommunicating therewith;

Fig. 8 is a transverse, sectional View, taken 10 substantially on theline 8--8 of Fig. 7, illustrating in detail the construction andarrangement of the ports;

Fig. 9 is a sectional view, taken substantially on the line 9-9 of Fig.7, illustrating in detail 15 the mounting of the improved brake cylinderconstruction and the relative positions of the ports communicatingtherewith.

With more particular reference to the drawings, the specific embodimentof the invention disclosed in Figures 1 to 3 thereof comprises a pair ofcylinders I0 and II arranged in substantially co-axial relation andadapted to receive pistons I2 and I 3, respectively. It has been foundpreferable in structures of this kind to form the cylinder I0 ofslightly larger diameter than the cylinder II in order that for adefinite predetermined uid pressure exerted internally of the cylinders,slightly greater force will be imposed upon one end of the brake shoe,which the cylinder serves to actuate than upon the other. 'I'his isdesirable in order to compensate for the wrapping eiect of the brakes onthe drums due to the rotation of the wheel and the cylinders aretherefore preferably proportioned to provide a resultant braking actionwhich is substantially uniform throughout the entire surface of thebrake shoe. The pistons I2 and I3 are provided with piston rods I4 andI5, respectively, which, as is conventional, serve to operate the brakeshoe with 40 which the apparatus is associated. As is usual instructures of this type, the pistons I2 and I3 may be maintained inpredetermined position within the cylinders by means of annularresilient closures I6 and Il, respectively, and are further 45positioned resiliently by means of a compression coil spring I8interposed therebetween. The cylinders are preferably flared at theirouter ends in order to provide a surface for effectively seating theclosure members I6 and Il.

The cylinders I0 and II are preferably supported by means of a pair ofbracket members 20 and 2l which have apertures therein adapted toreceive respectively the cylinders I0 and I I. These brackets 20 and 2|are formed of sheet 55 22 and 23, ythe purpose and function of which aredescribed in detail below. The duct 22 provides means for bleeding thecylinders i0 and Il and is utilized for the purpose of relieving airfrom the system during the assembly of the hydraulic brake system at thetime the braking fluid is introduced into the system. The duct 23provides means by which fluid may be introduced intocylinders duringoperation of the brakes and at all times maintains communication betweenthe conventional master cylinder and the cylinders III and Il.

As is best seen by reference to Figures 1 and 2, the cylinders I3 and Ilare mounted in `their respective brackets 20 and 2l with their adjacentends spaced apart slightly in order that the ducts 22 and 23 willcommunicate directly with the interior of the cylinders. 'I'he brackets20 and 2i are welded to their respective cylinders in order to effect atight closure with respect thereto and are then welded together face toface, in order to provide a substantially unitary structure.

, In order to increase the strength of the supporting strudsure as awhole, the rackets 2l and i 2l are preferably provided with integrallyformed wing portions 25 and 23, respectively, which are each bent atright angles to the body of the bracket and, as will hereinafter be moreclearly seen. serve to materially strengthen the structure as a whole. Abase plate 21, which is shown as being of substantially triangularconfiguration, is provided with an aperture adapted to receive themating portion of the brackets 2l and 2| and to slip over these matingportions a sumcient distance to seat on the edges of the wing lportions25 and 23. 'Ihe brackets 20 and 2| are eeh preferably provided withsubstantially identical upwardLv extending lugs 23, over which the baseplate 21 is adapted to slip in order that once the base plate has beenmounted on these members, it will servel to lock them in predeterminedposition.

'I'he base plate 21 ris preferably welded in substantially the positionshown, to the adjacent portions vof the brackets 23 and 2| to providetherewith a reinforced unitary structure for supporting the cylinders I3and Il.

In the assembly of the structure described above, I have found itparticularly Ydesirable to insert the cylinders III and Il into theapertures in their respective brackets, then to place the brackets faceto face and lock them in ilxed position by slipping the base platethereover. when the parts have thus been arranged in assembled position,I have found it particularly desirable to place welding material, suchfor example as copper wire, adjacent the joints in the structure, andthen subject the structure as a whole to a welding temperature in aninert atmosphere, during which time the copper wire adjacent the jointsmelts and flows into the cracks between the parts, effectively weldingthem together to provide a unitary structure and at the same timeeffectively sealing the cracks between the adjacent abutting parts ofthe structure as a whole.

After the above described parts have been welded together to provide -aunitarystructure, the ducts 22 and 23 are internally threaded to receivethe ilttings hereinafter described in detail.

A bolt 3l is provided which is adapted to be received within the feedduct 23. This bolt 3l has an axially extending channel or groove 3l cuttherein which permits the passage of duid through the duct 23 when thebolt 30 is screwed in position in this duct. The bolt 30 serves toposition and mount a iiuid supply fitting 32, whichhas an annularportion 33 surrounding the vshank of the bolt 30 and is preferablylocked in position upon the bracket 28 by screwing the bolt 30 into theinternally threaded duct 23. In order to eil'ect a tight seal betweenthe fitting 32, the bracket and bolt, washers 34 of suitableconstruction may be interposed therebetween.

From the above described construction, it will be apparent that iiuidmay be introduced through the iitting 32 into the annular spacesurrounding,the shank portion of the bolt 30. This iiuid may pass freelyalong the axially extending groove 3l into the duct 23 adjacent thecylinders il and Il.

As has been pointed out above, the adjacent ends of the cylinders arespaced apart slightly from one another and it will be consequentlyapparent that liquid may flow freely from the duct 23 into the interiorof the cylinders l0 and II through .this space.

'Ihe bleed duct 22 preferably has a valve seat 36 of conical form groundtherein and outwardly of the valve seat a threaded bushing 31 is screwedinto the threaded portion of the duct. This threaded bushing 'ispreferably formed conical at its inner end 33 to cooperate withV thevalve seat 33 to normally eiect a tight closure of the bleed duct 22 Thehollow bushing 31 is internally threaded and adapted to receive aclosure plug 33. which may be screwed thereinkand held in position bymeans 'of a conventional lock washer 40.

From the foregoing, it will be seen that when the brake system is beingassembled and lled with iluid the closure plug33may be removed and asuitable conduit threaded into the bushing interiorly thereof. Afterconnection of the conduit, the bushing may be unscrewed slightly, thusraising the conical end 33 from the valve seat 33 and permitting thefluid from the interior of the cylinder to ilow outwardly through theduct 22, through the valve 3B, into the interior of the bushing 31,vthrough suitable apertures in the bushing 33.

The above described structure makes possible the closing of the ductwhile the conduit is still connected to the bushing. .After the iluidhas been introduced into the cylinders I0 and Il, and the air bledtherefrom by means of the duct 22 and associated structure, the closureplug 32 may be screwed into position in the bushing and the conduit maybe removed.

In order to mount the above described assembly upon the brake housingstructure with which it is adapted to be used, a pair of cylindricalinternally threaded bosses 4I may be welded to the base plate 21.Suitable internally threaded bores extend through the base plate andthrough these bosses, which are adapted to receive bolts 42, serving tofirmly secure the structure as a whole 'to a brake housing structure 43on which it is mounted. v.

In the form of the invention illustrated in Figures 4 to 6, inclusive, amodied form of the invention is shown. This construction comprises abrake cylinder formed of a. single integral piece of sheet metalpreformed to provide cylindrical portions 4i and 46 disposed in co-axialrelation, with respect to each other, the cylinder 45 being of slightlylarger diameter than the cylinder 43.

This cylinder is mounted on a pair of mating bracket members 41 and 48,respectively, which bracket members have their adjacent surfacespreformed so that the two brackets will together provide a pair of ducts49 and 59, which serve to communicate with the interior of the cylinder.The edge portions of the brackets 41 and 48 are bent to provideout-turned wings 5| which lie substantially in the same plane and serveto provide a seat for a base plate 52, which is slipped over the bodyportion of the brackets substantially in the manner described inconnection withI the form of the invention shown in Figures 1 to 3. Itwill be noted that due to the fact that the cylinder construction shownin this form of the invention is of the one piece type, it is necessaryto cut away the wall thereof adjacent the ends of the ducts 49 and 58 topermit communication between the ducts and the interior of the cylinder.

As was the case in the form of the invention described above, the fluidsupply duct 58 is internally threaded to receive a bolt 53, which has anaxially extending groove or channel 54 therein to permit the passage offluid through the duct 58 when the bolt is screwed therein. The

bolt 53 serves to retain a fluid supply iitting 55 which hasan annularportion 56 adapted to surround the shank of the bolt and providescommunication with the axially extending groove 54 and duct to theinterior of the cylinder.

The brake cylinder assembly as a whole is mounted upon the brake housing58 with which it is associated by means of a pair of bolts 59 passingthrough suitable apertures in the housing 58 and threaded into suitablethreaded bores formed in the backing plate 53 and the wing portions 5|which are secured thereto. A sealing washer 62 is preferably interposedbetween the iiuid supply fitting and the mating brackets 41 and 48 towhich this fitting is secured. This washer may be formed of copper orother suitable similar material and is preferably provided with a pairof depending ears 64 which prevent relative rotation of the washer withrespect to the brackets on which it is mounted. I

The washer is provided with an aperture 65 adapted to register wtih thebleed duct 49 and it will be apparent by reference to Figure 6 that theiiuid supply fitting 55 has formed therein a bleed port 66 which isnormally adapted to be closed by a screw plug 61 locked therein by meansof a loci washer 68.

From the foregoing, it will be clear that the fiuid supply -iitting 55,as a whole, is rotatable about the bolt 53 which serves to secure it tothe mating brackets 41 and 48. In order to limit the amount of thisrotational movement, the fluid supply iitting is provided with a pair ofdepending lugs or ears 10, clearly seen in Fig. 4, which will abutagainst the side ofthe brackets 41 and 48 and limit rotational movementof the fluid supply iitting with respect to the brackets within arelatively short arc. y

It will be clear, however, that the extent of this arcuate movement issuiiicient to bring the bleed port 66 into, or out of registry with thebleed duct 49, and it will be seen that when the fluid supply iitting ismoved to a position where the port 66 and the duct 49 are out ofregistry, the face of the fluid supply fitting will serve to provide aneffective seal for the bleed duct 49.

At the time the iiuid is introduced into the system by means of theiiuid supply fitting 55, it will be seen that this iiuid will flow inthrough the fitting 55 into the annular space suriunding the shank ofthe bolt 50. From this annular space, it will be permitted to iiow alongthe axially extending groove 54 into the fluid supply duct 50 andconsequently, into the interior of the cylinder. A suitable conduit maybe connected to the bleed port 86 in place of the closure plug 61 and itwill be apparent that air may be bled off from the cylinder through theduct 4 9, aperture 65 in the washer, and bleed port 66, out through theconduit. After all air has been removed from the system, the fluidsupply fitting 65 may be swung around arcuately to effectively seal thebleed duct 49 and the conduit may be disconnected and screw plug 61inserted in order to protect the bleed port from accumulation of for`eign matter. The bolt 53 may then be tightened up to eii'ectively. andtightly seal the system.

In the form of the invention illustrated in Figures 7, 8 and 9, a stillfurther modiiied type of hydraulic brake cylinder' assembly is shownembodying some of the features shown in the forms of the inventiondescribed above.

In this form of the invention, it will be seen by reference to Figures 7`and 9 that the co-axially disposed cylinders are formed from a pair ofmating sheet metal stampings. These stampings are preferably 4extrudedto form cylinders 15 and 16 of slightly different diameters and havingmating iianges 11 and 18, respectively. These iianges are preferablyextended substantially on one side of the cylinder to form a pair ofradially extending mating brackets 19 and 80, which, at the time thestampings are formed, are provided, in their mating surfaces, withsemi-cylin drical grooves 8| and 82, which, together, form substantiallycylindrical ports communicating.

with the interior of the cylinders 15 and 16. These two stampingspreferably have their adjacent faces groundand secured together by theprocess of copper welding described in detail above.

In order to secure the cylinder assembly to a brake housing structure,the brake housing structure is provided with an aperture adapted toreceive the mating radially extending flanges 19 and 80. Screw bosses 85may be welded to the cylindrical surfaces of the cylinders 15 and 16,these bosses being internally threaded and adapted to receive bolts 86passing through suitable apertures in the wall of the brake housing 84.A fluid supply iitting .90 is provided, having a pair of aperturestherein adapted to register with the outer ends of the ducts 8| and 82.This uid supply fitting is provided Wtih a duct 9|, which communicateswith one of these apertures. A securing bolt 92 is threaded into thecylindrical duct 82, and, as was the case in the bolts above described,is provided with an axially extending channel 93, which serves to permitcommunication between the duct 82 and the feed duct 9|. The bleed duct8| is formed to provide a conical valve seat 95, which is adaptedto beclosed by a hollow externally threaded bushing 96 and screwed into theiiuid supply fitting 90 and into the cylindrical bore of the duct 8|.This bushing 96 is provided with a conical portion adapted to engage thevalve seat 95. Outwardly of this conical valve seat, the bushing isprovided with suitable apertures 91, which provide communication withthe interior of the bushing. The interior of the bushing is normallyclosed by means of a screw plug 98 threaded into the bushing and lockedin position by means of a suitable lock washer 99. As was the case inscribed in the modification shown in Figures 1 to 3, inclusive, of thedrawings.

It will be appreciated that the above described forms ofthe inventionare merely illustrative oi.' they generic concept presented. Many otherand further modifications, falling within the scope of the invention asdeiined in .the sub- Joined claims, will be apparent to those skilled inthe art.

What is claimed is:

1. Apparatus of the class described comprising a pair of cylindershaving their adjacent ends arranged in spaced relation, sheet metalbrackets for supporting said cylinders secured thereto and to eachother, said brackets preformed to provide a port therebetweencommunicating with the interior of said'cylinders.

2. In a brake cylinder assembly, a pair of cylinders having theiradjacent ends arranged cylinders having their ends arranged in spacedrelation, a pair of sheet metal brackets surrounding one of saidcylinders4 and secured thereto, said brackets being seclred togetheri'ace to face, and a base plate surrounding said brackets and securedthereto to provide .a unitary construction. A

4. In 'a brake cylinder assembly, a pair of cylinders having .theiradjacent ends arranged in spaced relation, a pair oi sheet metalbrackets each engaging one ci said cylinders and arranged i'ace to face,and a base plate engaging and surrounding said brackets, all of saidparts being welded together to provide a substantially unitarystructure.

5. In a brake cylinder assembly, a pair of cylinders, a pair of sheetmetal members serving to support said cylinders to provide portscommunicating with the interior thereof, one of said ports beinginternally threaded, a iiuid supply iitting associated with one of saidports, and means engaging the threaded interior oi said port formaintaining saidiluid supply fitting in communication with said port.

6. The method of forming a hydraulic brake,

cylinder assembly, which includes forming a pair of brackets havingmating grooves therein which together form ducts therebetween, insertingcylinders in said brackets, surrounding said brackets with a base plateto lock the same in predetermined relative position and simultaneouslywelding said members together to provide a unitary structure.

'1. The method of forming a hydraulic brake cylinder assembly, whichincludes forming a pair ot brackets having mating grooves therein whichtogether form ducts therebetween, inserting cylinders in said brackets,surrounding said brackets with a base plate to lock the same inpredetermined relative position, simultaneously welding said memberstogether to provide a unitary structure and internally threading saidducts.4

.JOHN w. LEIGHTON.

